Sound record



Patented Apr. 5, 1927.

UNITEDSATES MERCIAL COMPANY, A CORPORATION OF ILLINOIS.

SOUND anoonn.

No Drawin g.

The invention relates torecords such as are usedin phonographs, and'like mstru- 'ments, forthe reproduction of sound, and

improved, as well as the durability both ofv the record impressed upon the plate and the needles or points used in connection there with; and to render the plate less frangible and less liable to warping than it has hereto fore been possible to attain.

Plate records have been made of various materials mixed together as a plastic mass I and wrought into the desired 'plateform ,un'der pressure, the record being imprinted in the surface or surfaces in this process.

The materials employed have consisted usually of a granular filler constituting the principal ingredient, in quantity, a bonding agent, such as shellac, a coloring element, such as lamp black, and a material such as resin for rendering the surface glossy. In some instances, also, an ingredient of high specific gravity is added to increase the weight of the plate. Sometimes a fibrous 'material is added. The formulae for these record plates have been quite numerous, and ingredients of somewhat different character than those enumerated havebeen used.

The sound records heretofore in use have lacked smoothness of texture, with the result that the reproduction of the sounds,

' whether of speech or music, has been more or less raspy, and the friction, by the movement of the needle or point over the indentedsurface, has resulted in a too' rapid wearing of both parts, necessitating frequent changes of needles and resulting in the rapid deterioration of the impressed record.

The improved record forming the subject of this application is formed of a plastic, of which the filler is finely pulverized slate, preferably of extreme fineness, combined or mixed with any suitable bonding material, such as shellac, and with which may be used any other ingredients, as, for obtaining a desired color, finish or weight. A fibrous material, such as flock, may beadded,

bonding material.

Application filed March 31, 1923. Serial No. 629,220."

if desired, though I have foundit quite fea-.

sible to omit such an element,

The smoothness of the improved record varies With the degree of fineness'of the filler, the best results being obtained bythe use of slate reduced to what is sometimes known as air float fineness, that is to say, to the form of an impalpable powder which, being diffused in the air, will float for a considerable time. Pulverized slate. of a fineness known as 200 mesh, While less desirable, Will'result in a record superior in smoothnessto any-now being manufactured,

and will have the added advantages of less liability to fracture or warp .than has heretofore been secured.

Slate is usually found either green or red in color; Either variety may be used, and may be employed without'the use of a color- FREDERICK W. STONE, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR CENTRAL COM- ing material, or such a material may be employed according to the tasteof the manufacturer or user. r

V The specific gravity of the slate is such that plates of which it forms the major ingredient, as to quantity, will have the average weight which at the present time appears to be preferred, rendering it unnecessary to add an ingredient of greater weight.

The present inventionis not concerned JVltll the particular characterof any of the ingredients except the filler of pulverized slate. It is, of course, essential that there be present a suitable bonding agent, such as shellac, and'otheringredients may be added,

as for securing any desired surface finish, as

. preferred.

The improved record has the further advantage of cheapness of. manufacture, inasmuch as the tiller is less expensive thairmaterials heretofore used for this purpose, and the slate particles may be firmly united by the use of a smaller quantity of binding material than it has heretofore been found nec'- essary to use, thereby further reducing the cost of manufacture.

I claim as my invention A sound-record comprising in its composition a filler of pulverized slate reduced to a powder of. airfloat fineness, and a suitable FREDERICK W. STONE. 

